Index: wp-admin/includes/comment.php
===================================================================
--- wp-admin/includes/comment.php	(revision 25351)
+++ wp-admin/includes/comment.php	(working copy)
@@ -83,6 +83,13 @@
 	$comment->comment_post_ID = (int) $comment->comment_post_ID;
 
 	$comment->comment_content = format_to_edit( $comment->comment_content );
+
+	/**
+	 * The comment content before editing.
+	 *
+	 * @since 2.0.0
+	 *
+	 * @param string $comment->comment_content Comment content.
+	 */
 	$comment->comment_content = apply_filters( 'comment_edit_pre', $comment->comment_content);
 
 	$comment->comment_author = format_to_edit( $comment->comment_author );